Oil-switch.



L FLEISCHMANN & A. ELF'ES.

4OIL SWITCH.

APPLICATION FILED ocT. II. I9I2.

Patented Apr. 27, 191

Witnesses Inventors Lionel Fleischmann,

August. Elfes, @5MM/glee Tl-Ieirfit1. Onne LIONEL FLEISCHMANN AND AUGUST ELFES,VOF BERLIN,

GERMANY, ASSIG-NORS TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

OIL-SVITCH.

Specification of Letters Patent.

Patented Apr. 27, 1915.

Application tiled October 11, 1912. Serial No. 725,179.

To (dl @071cm 'it may Concern x Be it known that we, Lioisnr. FLEISCH- MANN, a citizen of the United States, residing at Berlin, Germany, and AUGUs'r Eures, a subject of the King of Prussia, residing at Berlin, Germany, have invented certain new and useful Improvements in Oil-Switches, of which the following is a specification.

Our invention relates to oil switches, and has for its object the prevention of the explosions which sometimes occur in oil switches upon the opening of circuits carrying large amounts of energy.

Various devices have been proposed and used to avoid explosions in oil switches. For example, the point of separation of the contacts has been inclosed in a special chamber having strong walls for resisting the explosive action of the arc, this chamber communic-ating with the body of oil in the tank through a comparatively small opening. Such constructions were developed upon the assumption that the explosion has its origin directly at the arc and is due principally to the direct explosive action of the arc acting below the level of the oil and tending to throw the oil out of the tank. Test-s have shown that this is not always the case. The heat of the arc produced in opening the circuit often causes decomposition of the loil and formation of combustible gases, which rise to the surface of the oil in the form of bubbles. Usually this formation' of combustible gases occurs without any injuriouseffeet. Sometimes it happens that. the arc causes glowing particles of metal or of carbon to be thrown off lfrom the electrodes or from the medium surrounding them. If such glowing particles of metal or carbon encounter the bubbles of combustible gas at the surface of the oil, the explosive mixture formed by the combustible gas and the air above the oil is ignited and an explosion occurs.

In accordance with our invention, the occurrence of explosions of oil switches'is prevented by making it impossible for the glowing particles t'o come in contact with the combustible gases at the surface of the oil; We may, for example, accomplish this result by placing above the point of separa tion of the contacts, partitions of some suitable material which will permit the escape of the bubbles of gas, but will catch and throw back any glowing particles produced l? ig. 2 is a transverse section of the switch shown in Fig. l; and F ig. 3 is a horizontal f section along the line 3-3 of the switch shown in Fig. l.

In the particular form of switch shown, an oil tank l is provided with a suitable cover which supports insulators for two sta' tionary contacts 2, which are submerged in oil.

A bridging contact 3 is mounted to move vertically into and out of engagement with the stationary contacts for the, purpose of closing and opening the circuit, as the bridging contact may be moved by any suitable and well known form of actuating mecha nisni, notshown in the drawing.

When the circuit is to be opened, the bridging contact 3 is moved downward, whereupon arcs are formed between the stationary contacts Q and the bridging Contact 3. To prevent these arcs causing severe exe plosions, we mount above the contacts and beneath the surface of the oil a suitable partition 4, which in the particular form of switch shown in the drawing, is made in the form of a woven wire net work of a suitable i-.f

mesh. As shown, this partition engages all of the walls of the oil tank l, consequently nothing can escape from the vicinity of the contacts to the surface of the oil except by passing through the net work 4. This net work is so woven as to offer but little ob-v struction to the passage of the combustible gases formed by the arc, but the glowing particles of metal or carbon carried upward by the rush of gases cannot easily get through, and will strike against the net workand rebou 1. As a result of this con struction, the glowing particles cannot come into contact with the combustible gases at 'the surface of the oil, and consequently explosions at the surface of the oil are prevented.

What we claim as new and desire to secure by Letters Patent of the United States, is,-

1. An electric switch comprising a vessel containing insulating fluid, coperating contacts separable in said fluid, and means mounted just below the surface of said 'fluid for permitting the escape of gases but preventing the passage of heated solid particles from the vicinity ofthe arc to the surface of said fluid.

2. An electric switch Comprising a vessel containing insulating fluid, coperating contacts separable in said fluid, and a screen mounted just below and near the surface of said uid to prevent heated particles from -the vicinity of the arc from rising to the surface of said fluid. v

3. An electric switch comprising a vessel containing insulating Huid, cooperating contacts separable beneath the surface of said fluid, and a woven wire screen mounted just below the surface of said fluid to. permit the passa e of gases but to prevent solid particles rom entering the air space above the oil. v

In witness whereof, we have hereunto set our hands this 27th day of September, 1912` LIONEL FLEISCHMANN AUGUST ELFES. Witnesses:

RICHARD VENMANN, WALTHER REINHARDT.

Copies of this patent may be obtained for ive cents eachpby addressing the Commissioner of Patents Washington, D. C. 

